Occasional truancy is recorded by head teacher - a bigoted person (6)
I believe the answer is:
racist
'a bigoted person' is the definition.
The answer and definition can be both people as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'occasional truancy is recorded by head teacher' is the wordplay.
'occasional' indicates alternate letters (letters taken at regular intervals or on occasion).
'is recorded by head teacher' becomes 'ist' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
The alternate letters of 'truancy' are 'rac'.
'rac'+'ist'='RACIST'
Can you help me to learn more?
(Other definitions for racist that I've seen before include "proponent of B&W crime drama?" , "Scar it (anag)" , "One ethnically biased" , "Hostile towards people of other ethnic origins" , "Bigot" .)